Laminamichaelia knowltoni, Uusitalo, 2025

Laminamichaelia knowltoni sp. nov.

( Figs. 38F, 40A–F, 41A–F)

Bimichaelia dimixsetosa ssp. texana McDaniel & Bolen 1983: 816 View in CoL , in part, unjustified synonymisation with Bimichaelia dimixsetosa View in CoL from Texas.

Description. Dorsum (n= 4 females, Figs. 38F, 40A, B). Length 400–560 µm; primary pattern polygonal, formed by large lamellae. Prodorsum: soft integument with 14 to 18 setae; crista with central area of polygons flanked by two strips; sensilla ve distally with 5–7 branches and basally barbed; intraspecific variation of 3 to 5 short setae in, plumate; lamellae in rows between ve and in; polygonal lamellar fields posterior to setae in sometimes with less organised rows. Intraspecific variation in the observed material is obvious, especially on in -area ( Figs. 38F vs. Fig. 40A).

Venter ( Figs. 40C–F). Sclerotised genital valves each with 9 genital setae; female progenital chamber with 2 short pairs of eugenital setae and 1 elongated pair (arrows) extruding from genital orifice; anal setae 6 per valve.

Gnathosoma ( Fig. 41F). Chelicerae straight; subcapitulum with two pairs of setae or slightly neotrichous; palpal solenidion inserted on a small protrusion, slightly constricted medially and in contact with one eupathidion, other eupathidion free.

Legs ( Figs. 41A–E). Solenidial formula for tarsi, tibiae, genua and femora on legs I, II, III and IV, respectively: 3B-2B-0-0, 2B-2B-2B-1B, 1C2\5P-1B2P-1P-1P, 2\4P-1B-0-0, high intraspecific variation on genua I and femora I, one of the genual solenidia might in some cases resemble a good-sized ceratiform solenidion; famulus I distal, placed abaxial.

Tritonymph (n=3). Length 500 µm, cleavage line present, one or two pairs of in -setae, three pairs of genital papillae, 5–8 genital setae per valve, 3–5 anal setae per valve, solenidial formula same as adult stage.

Type material. Holotype female, 3 paratype females and 3 paratype tritonymphs as Bimichaelia sp. from Utah juniper ( Juniperus osteosperma ) detritus, Providence Canyon , Cache Co., Utah, 30 April 1974, G.F. Knowlton. Deposited at the Acarology Laboratory, Ohio State University, coll. No. AL 5335, holotype on slide NA22 ( NA23 , NA24, NA 25 females, NA29, NA30, NA31 tritonymphs).

Additional material. Material from Texas, USA, is deposited at the Texas A&M University, with collection numbers TAMU-ENTO X164…: 1 deutonymph as Bimichaelia disetosa texana (written in pencil on the label), from sandy loam, shin oak ( Quercus havardii ), 1,5 miles N Paduach Route 83, Cottle Co., Texas, 30 May 1980, Eric G. Bolen, slide # X1641796; 1 deutonymph as Bimichaelia dimixsetosa from sandy loam, shin oak ( Quercus havardii ), 1,5 miles N Paduach Route 83, Cottle Co., Texas, 30 May 1980, Eric G. Bolen, slide # X1641817; 1 specimen as Bimichaelia disetosa texanas (written in ink on the label) from Dave’s plot s-6, Riparian Forest, Rob and Bessie Welder Foundation Wildlife Refuge, San Patricio Co., Texas, 15 June 1978, Eric G. Bolen, slide # X1648264; 1 tritonymph as Bimichaelia disetosa texanas (written in ink on the label) from control 1-A, mesquite grass ( Hilaria belangeri ), San Patricio Co., Sinton, Texas, Rob and Bessie Welder Foundation Wildlife Refuge, 19 April 1978, Eric G. Bolen, slide # X1647198; 1 deutonymph as Bimichaelia dimixsetosa from shin oak ( Quercus havardii ) grassland, 8.2 miles E Floydada where highway US 62 intersects with highway 70, Motley Co. Texas, 14 October 1979, Eric G. Bolen, slide # X1643935; 1 tritonymph as Bimichaelia dimixsetosa from light loam, Blue Grama grass ( Bouteloua gragilis ), Farm to Market road 168 N Olton, mile marker #163, Lamb Co., Texas, 12 October 1980, Eric G. Bolen, slide # X1642964.

Differential diagnosis. Laminamichaelia knowltoni is closely related to both L. arbusculosa (Grandjean) and L. furcula Uusitalo et al. , both of which have branched sensilla ve ( Fig. 40A vs. 42A; Uusitalo et al. 2020: fig. 119) but can be segregated from them by having famulus I in a distal position ( Fig. 41B), tibial baculiform solenidia aligned, one after another ( Fig. 41A, B, D, E) and piliform solenidia on tibiae I absent ( Fig. 41B). L. arbusculosa has famulus I close to solenidion ω2 ( Fig. 43B), tibial baculiform solenidia are side by side ( Fig. 43B, C, E­–H), and there are 3 piliform solenidia on tibiae I ( Fig. 43B, C). The African species L. furcula also has famulus I in a distal position ( Uusitalo et al. 2020: fig. 125), there is a clear gap between the two baculiform solenidia on tibiae I, II and III ( Uusitalo et al. 2020: figs. 125–126), and 1 piliform solenidion on tibia I ( Uusitalo et al. 2020: fig. 125).

Remarks. The arrangement of sensory organs on the prodorsum is often considered as a reliable area to recognise various species from each other, but based on the prodorsum only, it is impossible to make a reliable separation of Quartusmichaelia shibai , Q. dimixsetosa , Laminamichaelia knowltoni and L. arbusculosa from the American species, at least by low magnification. These species all have the anterior pair of sensilla ve furnished with cilia of various lengths and numbers, the number of setae on the in -area maybe anything between 2 and 8 depending on the developmental stage, as does the number of setae on the soft integument, and the integumental patterns also vary. Assumptions made based only on the prodorsum can cause errors as in L. knowltoni , which was marked as an undescribed species ‘ ful ’ in Uusitalo (2010). The 12 examined specimens, all from the same type locality and with the same date had similar prodorsal morphology in the in -area (cf. Fig. 38F and 38E for L. knowltoni and Q. dimixsetosa , respectively). Thus Uusitalo (2010) presumed observed variation was intraspecific variation in regards to the varying numbers of in -setae. However, on closer examination the material proved to be a mixture of two species: 7 of the specimens belong to Laminamichaelia knowltoni sp. nov., and 5 specimens to Qartusmichaelia dimixsetosa ( Uusitalo 2010: 68) , and similar misinterpretations have been made by authors with the Texan and Mexican materials of these species.

Some juveniles from Texas were considered to belong to L. knowltoni because the segments tibia I and II were without ceratiform solenidia, even though: the two baculiform solenidia on tibiae I and II were more or less diagonally (not strictly aligned); there was only two (not three) baculiform solenidia on tarsi I, but they were nontwisted; and/or they had only 1 or 2 (not 4) setae on the in -area.

Etymology. The species name (a patronymic genitive) is given in honour of George Franklin Knowlton (1901– 1987), Professor of Entomology at the University of Utah and collector of this new species.